Poor gas mileage

[Dewey]

Utterly ridiculous looking. But hey, it's a Ford, what do you want? View attachment 182430

That’s ridiculous

 

[Idahoktm]

Utterly ridiculous looking. But hey, it's a Ford, what do you want? View attachment 182430

Hey, this is a Ram forum. How about a TRX on 32's?

 

[HSKR R/T]

Hey, this is a Ram forum. How about a TRX on 32's?

View attachment 182446

I didn't get any pictures because I was working, but had a TRX running 28" drag radials in the factory wheels at drag strip last Saturday. Looks equally as stupid

 

[Fantastipotamus]

I really don't understand something. So the 22s...

-more wind resistance
-more weight

However they also

-turn faster (circumference) than smaller tires bringing engine RPM down at a given speed




Do they help or hurt mpg?

I will say anecdotally that I swapped in 22's on my Bighorn from the factory 20's, and my MPG has dropped. 1-2mpg estimated in both city/hwy. Both tires using road-focused all seasons, too. My 20's were still on the factory Bridgestone Duelers (pretty good tires IMO), new 22's are on Pirelli Scorpion WeatherActive XL's, which i've no experience with personally, but were 'best in category' on Tirerack.

Others have mentioned the circumference thing - but generally "wheel" is heavier than "tire", so the jump from 20 to 22" wheel will increase the weight:

apples to apples, for example:
My new tires in 285-45R22 - 39lbs
Same new tires in old size - 275-55R20 - 40lbs

wheels..
My old wheels - factory night edition 20's - 33lbs
New wheels are OEM replicas off TR in 22 - 40.5lbs

Assuming I kept the same tires (which I didn't, but it's the best way to illustrate it, because as others mentioned the tire design etc definitely factors in considerably) - by going from 20s to 22's, I've added ~6lbs of unsprung weight to each corner, which bounces around over bumps, spins fast, has to be accelerated, braked/slowed, and accelerated over and over.

Conceivably, it is possible that with a light enough larger circumference wheel you may reach parity between the two? But you might end up with wagon wheel looking setup which might.. say.. otherwise compromise important handling characteristics.

 

[spyder]

I didn't get any pictures because I was working, but had a TRX running 28" drag radials in the factory wheels at drag strip last Saturday. Looks equally as stupid

Yea, but at the strip when racing is actually functional. That blue monstrosity is just dumb. But...as with anything, if the person who paid for it earned the money in a legitimate way, I'm all for people spending however much they want on what they want. I blow money on plenty of stuff that some people think is dumb.

 

[PetePA]

I will say anecdotally that I swapped in 22's on my Bighorn from the factory 20's, and my MPG has dropped. 1-2mpg estimated in both city/hwy. Both tires using road-focused all seasons, too. My 20's were still on the factory Bridgestone Duelers (pretty good tires IMO), new 22's are on Pirelli Scorpion WeatherActive XL's, which i've no experience with personally, but were 'best in category' on Tirerack.

Others have mentioned the circumference thing - but generally "wheel" is heavier than "tire", so the jump from 20 to 22" wheel will increase the weight:

apples to apples, for example:
My new tires in 285-45R22 - 39lbs
Same new tires in old size - 275-55R20 - 40lbs

wheels..
My old wheels - factory night edition 20's - 33lbs
New wheels are OEM replicas off TR in 22 - 40.5lbs

Assuming I kept the same tires (which I didn't, but it's the best way to illustrate it, because as others mentioned the tire design etc definitely factors in considerably) - by going from 20s to 22's, I've added ~6lbs of unsprung weight to each corner, which bounces around over bumps, spins fast, has to be accelerated, braked/slowed, and accelerated over and over.

Conceivably, it is possible that with a light enough larger circumference wheel you may reach parity between the two? But you might end up with wagon wheel looking setup which might.. say.. otherwise compromise important handling characteristics.

LOL... quick question... what gear ratio do you have?

My thought process is that with 3.92 it could offset fuel consumption due to higher RPMs on the freeway... bigger diameter tires should slightly drop RPMs.

 

[HSKR R/T]

Yea, but at the strip when racing is actually functional. That blue monstrosity is just dumb. But...as with anything, if the person who paid for it earned the money in a legitimate way, I'm all for people spending however much they want on what they want. I blow money on plenty of stuff that some people think is dumb.

Yeah, but the guy who had it still couldn't drive and his times absolutely sucked.

 

[Idahoktm]

Others have mentioned the circumference thing - but generally "wheel" is heavier than "tire", so the jump from 20 to 22" wheel will increase the weight:

That only applies to some of the 32" SL tires. When you move up to an LT tire, 33" or bigger, or a tire that fits an 18" wheel, the tires weight quite a bit more than the wheels.

 

[Mountain Whiskey]

Hey, this is a Ram forum. How about a TRX on 32's?

View attachment 182446

Lord that is bad.whoever did that should be flogged.

 

[Mountain Whiskey]

I will say anecdotally that I swapped in 22's on my Bighorn from the factory 20's, and my MPG has dropped. 1-2mpg estimated in both city/hwy. Both tires using road-focused all seasons, too. My 20's were still on the factory Bridgestone Duelers (pretty good tires IMO), new 22's are on Pirelli Scorpion WeatherActive XL's, which i've no experience with personally, but were 'best in category' on Tirerack.

Others have mentioned the circumference thing - but generally "wheel" is heavier than "tire", so the jump from 20 to 22" wheel will increase the weight:

apples to apples, for example:
My new tires in 285-45R22 - 39lbs
Same new tires in old size - 275-55R20 - 40lbs

wheels..
My old wheels - factory night edition 20's - 33lbs
New wheels are OEM replicas off TR in 22 - 40.5lbs

Assuming I kept the same tires (which I didn't, but it's the best way to illustrate it, because as others mentioned the tire design etc definitely factors in considerably) - by going from 20s to 22's, I've added ~6lbs of unsprung weight to each corner, which bounces around over bumps, spins fast, has to be accelerated, braked/slowed, and accelerated over and over.

Conceivably, it is possible that with a light enough larger circumference wheel you may reach parity between the two? But you might end up with wagon wheel looking setup which might.. say.. otherwise compromise important handling characteristics.

That only applies to some of the 32" SL tires. When you move up to an LT tire, 33" or bigger, or a tire that fits an 18" wheel, the tires weight quite a bit more than the wheels.

Yep, I was going to say the same. I believe my 35 inch tires weigh more than my 18 inch aluminum wheel.

 

[Idahoktm]

Yep, I was going to say the same. I believe my 35 inch tires weigh more than my 18 inch aluminum wheel.

Most 35's weigh anywhere from 62-75lbs. 18" wheels are 30-40lbs.

 

[Fantastipotamus]

LOL... quick question... what gear ratio do you have?

My thought process is that with 3.92 it could offset fuel consumption due to higher RPMs on the freeway... bigger diameter tires should slightly drop RPMs.

I have 3.92's.. no dice there! but the circumference between my old tire setup and my new is either identical or nearly so, so it's only the weight difference in my case. Both are factory sizing so I didn't have to change the speedometer.

That only applies to some of the 32" SL tires. When you move up to an LT tire, 33" or bigger, or a tire that fits an 18" wheel, the tires weight quite a bit more than the wheels.

Right, that's very true. I destroyed my old trucks MPG via switching to some LT KO2's. Was brutal, went from 17-18hwy to 13-14. Looked great though!

i probably didn't state my point well - what i meant more was that given a consistent tire circumference, the weight increase going from an 20" wheel to a 22" will not come near the weight lost by going from a lower profile tire. My explanation was lacking. I didn't mean that the tire itself wouldn't outweigh the wheel - as you said there are plenty of examples where that's the case.

Now .. if you drop 5 figures on carbon fiber or magnesium wheels.. maybe there wouldn't be a drop in mpg? Who's got em??

 

[Trooper4]

Tire sizes, tread pattern, and air pressure, along with circumference, all play a role in mpg. Also, the narrower a tire and the weight of the tire, play a part. So, a narrow, bias ply, with highway tread, max inflation, and stock tire height, and driving with an egg under your foot, will maximize mpg. Just the way it is. But hey, it's a free world, and we can all eat at Burger King.

 

[theblet]

Tire sizes, tread pattern, and air pressure, along with circumference, all play a role in mpg. Also, the narrower a tire and the weight of the tire, play a part. So, a narrow, bias ply, with highway tread, max inflation, and stock tire height, and driving with an egg under your foot, will maximize mpg. Just the way it is. But hey, it's a free world, and we can all eat at Burger King.

Also road smoothness and wind.

 

[Mountain Whiskey]

Also road smoothness and wind.

And apparently temperature and humidity. Tread pattern. Driving on concrete vs asphalt. Elevation. A swarm of cicadas might be a challenge.

I'm sure an engineer somewhere will chime in on driving with or against the earth's rotation in conjunction with gravitational pull from the moon having some sort of effect on milage too.

 

[PetePA]

Roadies add incremental weight too.

 

[Trooper4]

Also road smoothness and wind.

Yes, but environmental variables are much harder to control.

 

[Kiwiaudio]

Been tracking for awhile and just as I expected.

View attachment 182140
Surprisingly after changing from 32” tires to 34.3” my gas mileage stayed virtually the same.

Ive started using fuelly also. Only have the last 4 fillups logged. How are you getting the accurate city/highway pie graph ? Do you enter that data yourself ?

 

[theblet]

Yes, but environmental variables are much harder to control.

Exactly. So we may never know if 89 gets better than 87. Too many variables.

Heck, one time I lost like 5 mpg just from the McDonald’s drive thru.

 

[Dewey]

Ive started using fuelly also. Only have the last 4 fillups logged. How are you getting the accurate city/highway pie graph ? Do you enter that data yourself ?

Yes. Just taking a guess. I don’t really do any actual stop/go big city driving like many do. Mostly passing thru small towns and country driving. I think a 60/40 mix is likely pretty accurate.